From afacb35f9bf87ae10f59091b18b001a4c114a589 Mon Sep 17 00:00:00 2001
From: Héctor Ramón Jiménez <hector0193@gmail.com>
Date: Sat, 12 Oct 2019 05:07:00 +0200
Subject: Draw sliders in `iced_wgpu`

---
 wgpu/src/renderer/slider.rs   | 125 +++++++++++++++++++++++++++++++++++++++---
 wgpu/src/shader/quad.frag     |   2 +-
 wgpu/src/shader/quad.frag.spv | Bin 3196 -> 3212 bytes
 3 files changed, 119 insertions(+), 8 deletions(-)

diff --git a/wgpu/src/renderer/slider.rs b/wgpu/src/renderer/slider.rs
index d1a30244..4ae3abc4 100644
--- a/wgpu/src/renderer/slider.rs
+++ b/wgpu/src/renderer/slider.rs
@@ -1,17 +1,128 @@
 use crate::{Primitive, Renderer};
-use iced_native::{slider, Layout, MouseCursor, Node, Point, Slider, Style};
+use iced_native::{
+    slider, Background, Color, Layout, Length, MouseCursor, Node, Point,
+    Rectangle, Slider, Style,
+};
+
+const HANDLE_WIDTH: f32 = 8.0;
+const HANDLE_HEIGHT: f32 = 22.0;
 
 impl slider::Renderer for Renderer {
-    fn node<Message>(&self, _slider: &Slider<Message>) -> Node {
-        Node::new(Style::default())
+    fn node<Message>(&self, slider: &Slider<Message>) -> Node {
+        let style = Style::default()
+            .width(slider.width)
+            .height(Length::Units(HANDLE_HEIGHT as u16))
+            .min_width(Length::Units(100));
+
+        Node::new(style)
     }
 
     fn draw<Message>(
         &mut self,
-        _slider: &Slider<Message>,
-        _layout: Layout<'_>,
-        _cursor_position: Point,
+        slider: &Slider<Message>,
+        layout: Layout<'_>,
+        cursor_position: Point,
     ) -> Self::Output {
-        (Primitive::None, MouseCursor::OutOfBounds)
+        let bounds = layout.bounds();
+
+        let is_mouse_over = bounds.contains(cursor_position);
+
+        let rail_y = bounds.y + (bounds.height / 2.0).round();
+
+        let (rail_top, rail_bottom) = (
+            Primitive::Quad {
+                bounds: Rectangle {
+                    x: bounds.x,
+                    y: rail_y,
+                    width: bounds.width,
+                    height: 2.0,
+                },
+                background: Background::Color(Color {
+                    r: 0.6,
+                    g: 0.6,
+                    b: 0.6,
+                    a: 1.0,
+                }),
+                border_radius: 0,
+            },
+            Primitive::Quad {
+                bounds: Rectangle {
+                    x: bounds.x,
+                    y: rail_y + 2.0,
+                    width: bounds.width,
+                    height: 2.0,
+                },
+                background: Background::Color(Color::WHITE),
+                border_radius: 0,
+            },
+        );
+
+        let (range_start, range_end) = slider.range.clone().into_inner();
+
+        let handle_offset = (bounds.width - HANDLE_WIDTH)
+            * ((slider.value - range_start)
+                / (range_end - range_start).max(1.0));
+
+        let (handle_border, handle) = (
+            Primitive::Quad {
+                bounds: Rectangle {
+                    x: bounds.x + handle_offset.round() - 1.0,
+                    y: rail_y - HANDLE_HEIGHT / 2.0 - 1.0,
+                    width: HANDLE_WIDTH + 2.0,
+                    height: HANDLE_HEIGHT + 2.0,
+                },
+                background: Background::Color(Color {
+                    r: 0.6,
+                    g: 0.6,
+                    b: 0.6,
+                    a: 1.0,
+                }),
+                border_radius: 5,
+            },
+            Primitive::Quad {
+                bounds: Rectangle {
+                    x: bounds.x + handle_offset.round(),
+                    y: rail_y - HANDLE_HEIGHT / 2.0,
+                    width: HANDLE_WIDTH,
+                    height: HANDLE_HEIGHT,
+                },
+                background: Background::Color(if slider.state.is_dragging() {
+                    Color {
+                        r: 0.85,
+                        g: 0.85,
+                        b: 0.85,
+                        a: 1.0,
+                    }
+                } else if is_mouse_over {
+                    Color {
+                        r: 0.9,
+                        g: 0.9,
+                        b: 0.9,
+                        a: 1.0,
+                    }
+                } else {
+                    Color {
+                        r: 0.95,
+                        g: 0.95,
+                        b: 0.95,
+                        a: 1.0,
+                    }
+                }),
+                border_radius: 4,
+            },
+        );
+
+        (
+            Primitive::Group {
+                primitives: vec![rail_top, rail_bottom, handle_border, handle],
+            },
+            if slider.state.is_dragging() {
+                MouseCursor::Grabbing
+            } else if is_mouse_over {
+                MouseCursor::Grab
+            } else {
+                MouseCursor::OutOfBounds
+            },
+        )
     }
 }
diff --git a/wgpu/src/shader/quad.frag b/wgpu/src/shader/quad.frag
index 987744db..849f581e 100644
--- a/wgpu/src/shader/quad.frag
+++ b/wgpu/src/shader/quad.frag
@@ -30,7 +30,7 @@ void main() {
     float radius_alpha = 1.0;
 
     if(v_BorderRadius > 0.0) {
-        radius_alpha = rounded(gl_FragCoord.xy, v_Pos, v_Scale, v_BorderRadius, 1.0);
+        radius_alpha = rounded(gl_FragCoord.xy, v_Pos, v_Scale, v_BorderRadius, 0.5);
     }
 
     o_Color = vec4(v_Color.xyz, v_Color.w * radius_alpha);
diff --git a/wgpu/src/shader/quad.frag.spv b/wgpu/src/shader/quad.frag.spv
index 063287b3..71b91b44 100644
Binary files a/wgpu/src/shader/quad.frag.spv and b/wgpu/src/shader/quad.frag.spv differ
-- 
cgit